Printing onto water-soluble film is known in the art. WO 2007034471 A2 (Icht) relates to a water-soluble detergent printed film comprising a film support and at least one print, being printed thereon and/or therein said film, said film comprises a water-soluble detergent adapted for effective cleansing of various human body and goods cleaning. U.S. Pat. No. 5,666,785 (Chris-Craft Industrial Products Inc.) relates to printing directly onto a water-soluble film. More particularly it relates to a method and apparatus for printing graphics and text directly onto water-soluble films while the film is in the process of being formed into a water-soluble container by a packaging machine. The printing process initiates when the packaging machine halts film transport temporarily during the form, fill and seal cycle that produces the water-soluble container. JP 55-034966 (Toppan Printing Co Ltd.) relates to printing onto fruits with distortionless impressions without causing damage to the fruits. This method involves printing onto a water-soluble film, pasting the film onto the fruits by using adhesive, and then removing the film by dissolution. Water-soluble detergent pouch preparation is known in the art. WO 02/40351 (Procter & Gamble) relates to a process for preparing water-soluble pouches. EP 1504994 B1 (Procter & Gamble) discloses a process at manufacturing a water-soluble multi-compartment pouch. US 2008/0041020 A1 (Procter & Gamble) relates to a water-soluble multi-compartment dishwashing pouch.
Off-line printing is used in labeling of packaging material and is accomplished by printing on packaging material in a distinct and separate process before the packaging material is installed on a packaging machine. Generally, this off-line printing process requires rolls of packaging material to be unwound, printed and then heated to dry. The packaging material is then rewound into rolls, and stored before delivering to the actual packaging process.
Water-soluble detergent pouches have been prepared from off-line printed water-soluble film. This process has been disclosed in co-pending patent application Ser. Nos. 12/270,534 and 12/270,547 (Procter & Gamble).
Off-line printing employs excessive process steps and significantly slows the process of producing packaging. Further, because the printing process is distinct from the actual packing process, the necessary equipment is remote from one another and therefore the entire operation requires a large area. Furthermore, excessive manipulation of the water-soluble film in unwinding and rewinding the film may affect the integrity and robustness of the water-soluble film itself. Loss of integrity and robustness will negatively affect the quality of the final product. Excess manipulation can also lead to increased scrap levels due to start-up and shut down of each process. Costs associated with handling this scrap must be considered. Another disadvantage of off-line printing is the storage of the printed material, which requires additional space to be stored. Off-line printing also creates a risk of printing an excess of a design.
There is a need for a method in which a water-soluble film can be continuously printed and then directly used in a pouch making process.